Kivy - 我的 ScrollView 不滚动

Question

我的 Python 应用程序在使用 Kivy 库时遇到问题。特别是，我试图在 TabbedPanelItem 中创建可滚动的元素列表，但我不知道为什么我的列表不滚动。

这是我的 kv 文件：

#:import sm kivy.uix.screenmanager
ScreenManagement:
     transition: sm.FadeTransition()
     SecondScreen:

<SecondScreen>:
    tabba: tabba
    name: 'second'
    FloatLayout:
        background_color: (255, 255, 255, 1.0)
        BoxLayout:
            orientation: 'vertical'
            size_hint: 1, 0.10
            pos_hint: {'top': 1.0}
            canvas:
                Color:
                    rgba: (0.98, 0.4, 0, 1.0)
                Rectangle:
                    pos: self.pos
                    size: self.size
            Label:
                text: 'MyApp'
                font_size: 30
                size: self.texture_size

        BoxLayout:
            orientation: 'vertical'
            size_hint: 1, 0.90
            Tabba:
                id: tabba

        BoxLayout:
            orientation: 'vertical'
            size_hint: 1, 0.10
            pos_hint: {'bottom': 1.0}
            Button:
                background_color: (80, 1, 0, 1.0)
                text: 'Do nop'
                font_size: 25


<Tabba>:
    do_default_tab: False
    background_color: (255, 255, 255, 1.0)

    TabbedPanelItem:
        text: 'First_Tab'
        Tabs:

    TabbedPanelItem:
        text: 'Second_Tab'
        Tabs:

    TabbedPanelItem:
        text: 'Third_Tab'
        Tabs:


<Tabs>:
    grid: grid
    ScrollView:
        scroll_timeout: 250
        scroll_distance: 20
        do_scroll_y: True
        do_scroll_x: False
        GridLayout:
            id: grid
            cols: 1
            spacing: 10
            padding: 10
            Label:
                text:'scroll'
                color: (0, 0, 0, 1.0)
            Label:
                text:'scroll'
                color: (0, 0, 0, 1.0)
        Label:
            text:'scroll'
            color: (0, 0, 0, 1.0)
        Label:
            text:'scroll'
            color: (0, 0, 0, 1.0)
        Label:
            text:'scroll'
            color: (0, 0, 0, 1.0)
        Label:
            text:'scroll'
            color: (0, 0, 0, 1.0)
        Label:
            text:'scroll'
            color: (0, 0, 0, 1.0)
        Label:
            text:'scroll'
            color: (0, 0, 0, 1.0)
        Label:
            text:'scroll'
            color: (0, 0, 0, 1.0)
        Label:
            text:'scroll'
            color: (0, 0, 0, 1.0)
        Label:
            text:'scroll'
            color: (0, 0, 0, 1.0)
        Label:
            text:'scroll'
            color: (0, 0, 0, 1.0)
        Label:
            text:'scroll'
            color: (0, 0, 0, 1.0)
        Label:
            text:'scroll'
            color: (0, 0, 0, 1.0)
        Label:
            text:'scroll'
            color: (0, 0, 0, 1.0)
        Label:
            text:'scroll'
            color: (0, 0, 0, 1.0)
        Label:
            text:'scroll'
            color: (0, 0, 0, 1.0)
        Label:
            text:'scroll'
            color: (0, 0, 0, 1.0)
        Label:
            text:'scroll'
            color: (0, 0, 0, 1.0)
        Label:
            text:'scroll'
            color: (0, 0, 0, 1.0)
        Label:
            text:'scroll'
            color: (0, 0, 0, 1.0)
        Label:
            text:'scroll'
            color: (0, 0, 0, 1.0)
        Label:
            text:'scroll'
            color: (0, 0, 0, 1.0)
        Label:
            text:'scroll'
            color: (0, 0, 0, 1.0)
        Label:
            text:'scroll'
            color: (0, 0, 0, 1.0)

这是我的 .py 代码：

__author__ = 'drakenden'

__version__ = '0.1'

import kivy
kivy.require('1.9.0') # replace with your current kivy version !

from kivy.app import App
from kivy.lang import Builder
from kivy.uix.screenmanager import ScreenManager, Screen, FadeTransition
from kivy.properties import StringProperty, ObjectProperty,NumericProperty
from kivy.uix.tabbedpanel import TabbedPanel
from kivy.uix.boxlayout import BoxLayout
from kivy.uix.button import Button
from kivy.utils import platform
from kivy.uix.gridlayout import GridLayout
from kivy.uix.label import Label
from kivy.uix.scrollview import ScrollView

class Tabs(ScrollView):
    def __init__(self, **kwargs):
        super(Tabs, self).__init__(**kwargs)


class Tabba(TabbedPanel):
    pass


class SecondScreen(Screen):
    pass

class ScreenManagement(ScreenManager):
    pass

presentation = Builder.load_file("layout2.kv")

class MyApp(App):

    def build(self):
        return presentation


MyApp().run()

我在哪里/什么地方做错了？

（也接受UI改进的意见和建议）

Answer 1

我自己已经有一段时间没有使用猕猴桃了，但如果我没记错的话： 因为 ScrollView 中的布局应该比滚动视图更大 例如 ScrollView 宽度：1000px，GridView 1100px。 所以可以滚动 100px

Answer 2

网格布局应该有一个定义的高度以在滚动视图内滚动

ScrollView:
        scroll_timeout: 250
        scroll_distance: 20
        do_scroll_y: True
        do_scroll_x: False

        GridLayout:
            id: grid
            cols: 1
            height: self.minimum_height # this helps scroll allow scroll if grid layout height becomes more than scrollview.